iv Preface 



major piece of work other minor points may 

 be gatherd around it and are readily ab- 

 sorbd. 



In this collection of agricultural material 

 it is interesting to note the points that are 

 brot home to the student as the work 

 develops Among these are oxidation, neu- 

 tralization, distillation, crystallization, sat- 

 uration, chemical calculations, metathesis, 

 mass action, double salts, equilibrium and 

 colloids. By making a process necessary 

 to the production of material the student 

 must grasp it or fail in the experiment. 

 Take the seemingly simple matter of satura- 

 tion. It is but the work of a minute to ex- 

 plain what is meant by the process; the 

 student will give an intelligent expression of 

 the phenomenon in a second minute; how- 

 ever, when in the laboratory he is making a 

 preparation from two others, the success of 

 which depends upon the preparation of two 

 saturated solutions, then, and not until then, 

 does the student understand saturation. 



Only about half of the students entering 

 this college have had farm experience. It is 

 difficult to interest a student in the prepara- 

 tion of superphosphate or Bordeaux mixture 

 unless he knows something of its use, hence 

 the amount of space given in the notes to the 

 practical use of each substance. This does 



